Coil tuner rod



0 May 11, 1965 G. M. RAPATA 3,182,516

COIL TUNER ROD Filed April 20, 1962 INVENTOR. GEORGE M. R PATA ATTORNEY United States Patent Tee 3,182,516 COIL TUNER ROD 0 George Martin Rapata, Park Ridge, IiL, assignor to Illinois Tool Works Inc., Chicago, Ill., a corporation of Delaware Filed Apr. 20, 1962, Ser. No. 189,152 8 Claims. (Cl. 74-1035) problem because of the miniature size of such items has been to find suitable means for controlling the core within the insulated tube. Various means of attachment have been utilized, but many pose problems in assembly and "are uneconomical.

It is an object of this invention to provide a one piece insulated control member capable of ready assembly with a ferrite or carbon inductive core.

A further object of the invention is to provide an economical control rod adapted to be complementarily accepted in a core for use within a variable inductance coil.

Still another object is to provide a device of the type described which can be readily disassembled, if necessary, from the core.

Other objects will become apparent to those skilled in art when the specification and claims are read in conjunction with the appended drawing wherein:

FIG. 1 is an exploded view of a device embodying the principles of the present invention;

FIG. 2 is an exploded view, in partial elevational section, of such a device prior to assembly with a core;

FIG. 3 is an elevation in partial section of the device in FIG. 2 in assembled position;

FIG. 4 is an end view taken along line 4-4 of FIG. 2, showing the cross sectional configuration of the bore in the core;

FIG. 5 is an exploded view in partial section of a second device embodying the principles of this invention; and

FIG. 6 is an elevation in partial section of the device shown in FIG. 5 in assembled relation.

One example of the present invention as seen in FIGS. 1 through 4 includes as inductance coil 10, a core 22 and control rod 30. Said inductance coil 10 has an insulated tube 12 wound on its exterior surface by a plurality of wire windings 14. Wire windings 14 at one end have appropriate leads 16 adapted to be attached to a power source, not shown, as is well known in the art. Tube 12 is provided with a pass-through bore 18 having suitable thread engaging means therein for purposes set forth hereinafter.

Core 22 is generally manufactured from carbon or ferrite impregnated materials as is well known in the art. In the present embodiment core 22 has a plurality of screw threads 24 formed on its exterior surface complemental to threaded bore 18. A non-circular bore 26 extends from one end of core 22 to its opposite end and may be hexagonal in shape, as shown, although it will be recognized that other non-circular shapes can be used with equal facility.

Control rod 30 has an elongated shaft with handle means 32 at one end thereof. Extending from handle means 32 is a first shaft portion 34. Portion 34 in the present instance is substantially uniform in diameter throughout 3,182,516 Patented May 11, 1965 its length and preferably is circular in cross section to avoid accidental entanglement with adjacent components as well as to provide structural rigidity to the shaft. A hook-like second shaft portion 36 extends from the juncture with the first portion 34 to the free end of the shaft. Portion 36 has a smaller cross sectional area than first portion 34 and at their juncture they are coaxial so as to provide circumferentially extending shoulder means 38. The second portion 36 is substantially non-circular in cross section, in this embodiment, and complementary to hexagonal bore 26 of the core through which it will pass. The hook-like portion 36 on its upper surface is provided with a plurality of radially stepped portions axially spaced starting at a point intermediate its length and steps progressively upwardly to the extremity or free end of said portion. These stepped sections provide a plurality of spaced shoulder means 40 in opposition to the first mentioned shoulder means 38. The under surface 42 of second portion 36 curves upwardly from its initial intermediate point designated 44 to a point above the axis of the control rod where it joins the last step of the upper surface in a point giving the illusion of a curved spear barbed on one side.

Control rod 39 is preferably fabricated from an organic plastic material, such as nylon, which provides not only the quality of insulation necessary in such an application, but also gives a degree of flexibility to the hook-like second portion 36 necessary for the present device. The cylindrical configuration of first portion 34 is essentially rigid.

In operation, the hook-like portion 36 is fed into the complementary bore 26 of the core 22 and said portion 36 is flexed downwardly to a substantially straight line configuration. As the hook end is telescoped within the bore of the core, the shoulder means 40 will snap upwardly, as viewed in the drawings, into engagement with the end face of the core as said shoulder means passes through the terminal end of the bore. This is due to the resiliency of the material from which the control rod is made. As can be seen, the plurality of stepped shoulder means 40 permit the use of the same control rod with a variety of different lengths of cores. Thus, a single control rod can be stocked for a variety of models. After one of the shoulders 40 has snapped upwardly into engagement with the end face in the fashion shown in FIG. 3, the opposite end of the core is in opposition to the first mentioned shoulder 38 so that the control rod 30 is effectively captured, within limits, against axial and rotative movement relative to the core. The core is then inserted within the bore 18 of the insulated tube and by rotation the threads 24 draw the core into the appropriate position.

A second embodiment of the invention is shown in FIGS. 5 and 6 wherein similar numerals will be used to designate similar parts with the addition of the suffix a. In this embodiment the control rod 30a has handle means 32a, a first shank portion 34a and a hook-like second shank portion 36a. In this embodiment the hooklike second portion 36a is generally circular in cross section as opposed to the noncircular section of the corresponding part in the first embodiment. A third portion 46 is provided on the shank of the control rod and is positioned intermediate the extremities of the first portion 34a. The third portion 46 is greater in diameter than said first portion and is provided with a plurality of male screw threads for purposes best set forth hereinafter.

The core 22a in this embodiment is substantially cylindrical in configuration on its exterior surface and is provided with a cylindrical bore 26a complementary to the hook-like portion 36a. The tube 12a of the variable inductance coil has windings 14a positioned along its length as was the case in the first embodiment.

At one end of tube 12a there is provided a thread engaging means 48 which can be of any suitable configuration as is well known in the art. In the present instance it takes the form of a tubular sheet metal clip having means 49 for engaging the exterior of the insulated tube 12a and is provided with suitable thread engaging means 50 complementary to the third portion 46. In this embodiment the threaded third portion 46 is screwed into the thread engaging means 50 until the hook-like second portion 36:: extends beyond the opposite terminal end of the bore 13a in the tube 12a. The hook-like portion is then telescoped within the bore 26a of the core and the control rod rotated for movement in a retrograde direction to the left as seen in FIG. 6 until the core 22a is in proper position relative to the coils 14a. Other modes of assembly will be apparent, for example, the thread engaging means 48 can be mounted on the third portion 46, the core 22a telescoped relative to the hook-like portion 36a and the entire subassembly slid into proper position with the means 49 engaging the external surface of the tube 12a. Variable inductance tuning coils of this general type are well known in the radio and television art and the embodiments used as examples of the teachings of the present invention are merely illustrative and other examples will undoubtedly be apparent to those skilled in the art. It is the intent of the inventor to be limited only by the appended claims when viewed in the light of the prior art.

I claim:

1. A one piece plastic rod adapted to be accepted within the complementary bore of a controlled device including an elongated shaft, handle means at one end of said shaft, said shaft having a first portion extending from said handle means to a point intermediate the length of said shaft, said shaft further having a flexible hook-like second portion extending from said first portion to the free end of the shaft and presenting a convex and concave side, said concave side of said hook having a plurality of axially spaced shoulder means, each of said shoulder means being successively stepped radially outwardly as they progress towards the free end of said hook, the convex surface of said second hook portion being curved and substantially smooth and continuous.

2. A device of the type claimed in claim 1 wherein said second hook-shaped portion is polygonal in cross section at any point throughout its length.

3. A device of the type claimed in claim 1 wherein a third portion is provided intermediate opposite ends of said first portion, said third portion being greater in diameter than said first portion and having a threaded impression thereon.

-4. A device of the type claimed in claim 1 wherein said second portion has a smaller diametral extent than said first portion resulting in shoulder means at the juncture of said portions.

5. A device of the type claimed in claim 4 wherein said second portion further being polygonal in cross-section at any point throughout its length, said polygonal second portion having a cross sectional area in its stepped shoulder portions which does not exceed the cross sectional area of said second portion adjacent its juncture with said first portion, whereby, said hook-like second portion can be flexed into substantially straight line relation for acceptance within a complementary bore in said controlled device and one of said stepped shoulder means will engage one end of said controlled device while the shoulder means at the juncture of said first and second portions will engage the opposite end face of said controlled device.

6. A one piece plastic control rod for tuning cores in variable inductance coils wherein said core has a through bore and said coil has a coil form with a plurality of conductive windings around its exterior surface and adapted to accept said core internally for axial movement within the coil form, said control rod having an elongated shank, a handle integral with one end of said shank, said shank having a first portion extending coaxially from said handle, said shank having a second portion of smaller cross sectional dimension than said first portion, shoulder means at the juncture of said first and second portions, said shank having a third portion extending from said second portion to the free end of the shank and tapering upwardly relative to the axis of the shank,'said second and third portions having upper and lower surfaces with said third portion on its lower surface commencing with the lower surface of the second portion below the axis of said shank and curving upwardly'to a point lying in a plane located above the axis of the shank, the upper surface of said third portion being stepped in a plurality of increments upwardly above the upper surface of said second portion to a point co-planar with the last mentioned point on the lower surface, said stepped increments providing a plurality of shoulder means spaced along the axis and spaced progressively radially outwardly from one another as measured from said axis, said third portion being adapted to flex downwardly and be complementarily accepted within the bore of the core, one of said stepped shoulder means engaging and end surface of said core while the shoulder means at the juncture of the first and second portions is adapted to engage the opposite end surface of the core whereby movement of the plastic control rod will move the core within the coil form to produce variation in inductance in the windings.

7. A device of the type claimed in claim 6 wherein said core bore and said second and third portions are provided with complementary non-circular configurations, internal thread means in said coil form, the outside surface of said core being provided with thread means for complementary engagement with said internal thread means in said coil form, whereby rotation of said handle will result in rotation and axial movement of said core within said coil.

8. A device of the type claimed in claim 6 wherein said shank is provided with a fourth portion located intermediate the extremities of said first portion and being of greater diameter than said first portion, screw threaded means associated with said coil, said fourth portion having means for complementarily engaging said screw threaded means associated with said coil, said second and third portions and said core bore being generally circular in complemental cross section whereby rotation of said handle and its associated threaded shank results in axial movement of said core relative to the coil.

References Cited by the Examiner UNITED STATES PATENTS 346,605 8/ 86 Perry et al. 2-8758 2,313,358 3/43 Periman 5 2,451,591 10/ 48 Tinnerman et a1 855 X 2,509,202 5/50 Arens 74503 2,596,940 5/52 Paupitch 855 2,782,020 2/57 MoCandless 64-4 X 2,909,957 10/59 Rapata 85-5 2,918,808 12/59 Botti 74501 BROUGHTON G. DURHAM, Primary Examiner, 

1. A ONE-PIECE PLASTIC ROD ADAPTED TO BE ACCEPTED WITHIN THE COMPLEMENTARY BORE OF A CONTROLLLED DEVICE INCLUDING AN ELONGATED SHAFT, HANDLE MEANS AT ONE END OF SAID SHAFT SAID SHAFT HAVING A FIRST PORTION EXTENDING FROM SAID HANDLE MEANS TO A POINT INTERMEDIATE THE LENGTH OF SAID SHAFT, SAID SHAFT FURTHER HAVING A FLEXIBLE HOOK-LIKE SECOND PORTION EXTENDING FROM SAID FIRST PORTION TO THE FREE END OF THE SHAFT AND PRESENTING A CONVEX AND CONCAVE SIDE, SAID CONCAVE SIDE OF SAID HOOK HAVING A PLURALITY OF AXIALLY SPACED SHOULDER MEANS, EACH OF SAID SHOULDER MEANS BEING SUCCESSIVELY STEPPED RADIALLY OUTWARDLY AS THEY PROGRESS TOWARDS THE FREE END OF SAID HOOK, THE CONVEX SURFACE OF SAID SECOND HOOK PORTION BEING CURVED AND SUBSTANTIALLY SMOOTH AND CONTINOUS. 